Field of the Invention
The present invention relates to a parking lock system comprising a rotating shaft that is rotatably supported on a transmission case and transmits driving force from a drive source to a driven wheel, a parking gear that is provided on the rotating shaft, an operating shaft that is axially slidably supported on the transmission case and has opposite end parts disposed at positions displaced in a fore-and-aft direction of a vehicle body, a link member that swings due to sliding of the operating shaft, and a parking pawl that engages with the parking gear by swinging of the link member and non-rotatably restrains the rotating shaft.
Description of the Related Art
In such a parking lock system, an operating shaft slides in an axial direction due to an inertial force in a fore-and-aft direction generated when a vehicle is involved in a collision or undergoes sudden braking, and Japanese Patent Application Laid-open No. 2015-124881 has made known an arrangement in which in order to prevent the parking lock system from suddenly operating, damping means for damping axial sliding of the operating shaft is provided on one end part of the operating shaft.
However, in the above arrangement, since the damping means for damping axial sliding of the operating shaft includes a first space housing the operating shaft, a second space separated from the first space via a partition wall, a support hole formed in the partition wall on the first space side and slidably supporting one end part of the operating shaft, a throttle hole providing communication between a base part of the support hole and the second space, and a variable volume chamber formed between said one end part of the operating shaft and the base part of the support hole, not only is it troublesome to set a diameter of a small throttle hole and machine it, but it is also necessary to employ a seal member for sealing the variable volume chamber, and there is thus a possibility that cost will increase.